Biology I
Basic Chemistry Review
Henrico County Public Schools
What is matter?
- Anything that has mass and takes up space.
What are atoms?
The smallest particles of an element that take on unique characteristics.
What are subatomic particles?
Protons
Neutrons
Electrons
Which charge do protons have?
positive
Which charge do electrons have?
negative
Which charge do neutrons have?
No charge
How can physical property be described?
Changes in:
Size
Texture
Shape
Color
Weight
Mass -Density
How can chemical property be described?
Irreversible changes in composition:
Structure
Complexity
What is an example of a compound element?
(Molecule)
H2O
How do you calculate the total number of elements in a compound element? (Molecule)
- (add number subscripts of the element)
- H
2O= (2)+(1) = 3
How do you calculate the total mass of a compound element?
- (using number subscripts and atomic weight)
H
2O = (2x1) + (1x16) = 18
What is the relationship between the number of protons and the atomic number?
The relationship is synonymous
Hydrogen has 1 proton therefore it has an atomic number of 1.
What is the ratio of protons to neutrons in the nucleus of an atom?
Which subatomic particle differs in an isotope than that of the original elements atomic composition?
- The number of neutrons differ
Where can the name of an element be found on the periodic table?
Where can the atomic weight of an element be found on the periodic table?
- At the bottom of the square
Where can the atomic number of an element be found on the periodic table?
- Below the name and above the symbol
Where can the symbol of an element be found on the periodic table?
- In the middle of the square in large print
Which kind of attraction allows for a covalent bond?
- Electron sharing
- Elements are joined together
Which attraction allows for an ionic bond?
lost and gained electrons creating a negatively charged or positively charged atom.(Ion.)
Oppositely charged attraction between ions!
What chemical reactions are caused by certain chemical bonds?
IONIC CHEMICAL BOND(CHARGE BASED)
Table salt - Na+ and Cl- = NaCl
COVALENT CHEMICAL BOND (ELECTRON SHARING)
water - H20 = H-O-H
If two compounds meet a chemical reaction results!
HCl + NaOH --> NaCl +H2O
Substance Product
Hydrochloride and sodium hydroxide yields table salt and a water molecule.
What are endothermic reactions?
Energy used to make something
Plants form their own carbohydrates by endothermic reactions. (photosynthesis)
What are exothermic reactions?
Releases energy or is created.
Shivering in a cold room is your body’s way of creating heat, which is an exothermic reaction to cold temperature.
Mixtures what are they?
A combination of two or more substances uniformly distributed.
Parts of a mixture?
Solute - is the substance being dissolved.
Solvent - is the substance doing the dissolving.
Types of Solutions
- Gas-gas air
- Liquid-gas moist air
- Gas-liquid soda water
- Liquid-liquid vinegar
- Solid-liquid brine
- Solid-solid sterling sliver
Most abundant solvent on earth!
Water
65-95 % the human body
Acids ?
compounds that release hydrogen ions (H+)
Bases?
compounds that release hydroxide ions (OH-)
Salts?
compounds that release ions other than hydrogen or hydroxide ions
pH scale?
A standard measurement of the concentration of hydrogen ions (H+) in a solution.
0 to 14
Basic -13 bleach, 11 ammonia, 9 baking soda, 8 egg whites
Neutral -7.5 Blood, 7 Water
Acid -, 4 tomato juice, 3 vinegar, 2 lemon juice, .5 battery acid